Drafting instrument



March 13, 1945.

' A. WALDMAN 2,371,485

DRAFTING INSTRUMENT Filed Dec. 2, 1943 Inventor liq/201v Mn omm/ By fizmaoliwm WW 19m Patented Mar. 13, 1945 UNITED STATES PATENT oFFlcl:

DRAFTING INSTRUMENT Aaron Waldman, New York, N. r.

Application December 2, 1943, Serial No. 512,610

2 (Halms.

The present invention relates to new and useful improvements in drafting instruments, and has for its primary object to provide, in a manner as hereinafter set forth, novel means for facilitating the rapid and accurate drawing of radio and other symbols.

Other objects of the invention are to provide a drafting instrument of the aforementioned character which will be simple in construction, strong, durable, compact, and which may be manufactured at low cost.

All of the foregoing and' still further objects and advantages of the invention will become apparent from a study of the following specification, taken in connection with the accompanying drawing wherein like characters of reference desig-- nate corresponding parts throughout the several views, and wherein:

Figure 1 is a top plan view of a drafting instrument constructed in accordance with the present invention.

Figure 2 is a fragmentary view in section, taken substantially on the line 2--2 of Figure 1.

Figure 3 is a fragmentary sectional view, taken substantially on the line 9-9 of Figure 1.

Figure 4 is a detail view in Plan of one of the slidable coil symbol plates.

Figure 5 is a cross sectional view, taken substantially on the line 5-5 of Figure 1.

Referring now to the drawing in detail, it will be seen that the embodiment of the invention which has been illustrated comprises a triangle I of Celluloid or other suitable material, which triangle may be of any desired dimensions.

As illustrated to advantage in Figure 5 of the drawing, the triangle l comprises comparatively thin portions 2 providing raised or elevated surfaces on the bottom or lower face of said triangle. The portions 2 of the triangle l have formed therein slots and openings, and groups of slots and openings, which conform in shape and arlhe plates 8 have formed therein parallel series of substantially segmental openings 9 with slots l0 therebetween. In one longitudinal edge,

rangement to radio or other symbols, as at 3. The

slots or openings 3 are for the reception of a pen or pencil. The triangle l is further provided with a plurality of circular openings 4 of different sizes.

In one endportion, the triangle i has formed therein elongated openings 5 of uniform width and diameter with which right angularly extending slots 6 communicate at an intermediate point. As best seen in Figure 2 of the drawing, the longitudinal walls of the openings 5 are grooved, as at I, to slidably receive the longitudinal marginal portions of thin, resilient plates 9 of Celluloid or other suitable material.

the p tes 8 are further provided with spaced notch s H. The notches II are for the reception f slidable latches l2 which, as illustrated in Fig re 3 of the drawing, are dovetailed into the slots 8. Operating lugs l3 are provided on the slidable latches l2.' Substantially similar ,elements ll are provided on the slidable plates 8.

It is thought that the manner in which the d vice is used will be readily apparent from a consideration of the foregoing. Briefly, to draw the different symbols, a pen or pencil is inserted through the slots and openings 3. ,The raised surface portions 2 of the triangle I prevent smearing when ink drawings are being made. In the embodiment shown, the symbols 3 are those of a battery, as at IS, a resistor l8, et cetera. "I'he slidable plates 8 with the substantially segmental openings 9 and the slots Ill therein are for making different sizes of radio coil symbols. To draw a coil symbol, the plate 8 which is to be used is locked in one of its positions through the medium or the latch l2 which i engaged in one of the notches II. An instrument is inserted through the openings 9 and substantially c-shaped segments are drawn. The latch I2 is then retracted, the plate 5 is shiftedlongitudinally and again locked by engaging the latch II in the other notch II. Th operation is then repeated and a' line is drawn in the slot III with the result that the substantially c-shaped segments which were drawn last overlap and Join the ends of those which were t:irst drawn and thus a complete coil symbol is ha It is believed that the manyadvantages of a drafting instrument constructed in accordance with the present invention will be readily understood, and although a preferred embodiment of the device is as illustrated and described, it is to be understood that changes in the details of construction and in the combination and arrangement of parts may be resorted to which will fall within the scope of the invention as claimed.

What is claimed is:

l. A drawing instrument comprising a sheet having an elongated opening therein and further having a. slot therein communicating with the opening, a plate slidable in the opening, said plate having openings therein for the reception of a drawing instrument, and a latch slidable in the slot and engageable with the plate for releasably. I

scribed comprising a transparent triangle having an elongated opening therein and further having a slot therein communicating with the opening at an intermediate point, the longitudinal walls 01 the opening having grooves therein. an elongated plate elidably mounted in the grooves and having notches in one oi its longitudinal edges at spaced points, and a latch aiidably mounted in the slot and engageable selectively in the notches ior releasably securing the plate against sliding movement in the triangle, said plate having openinge therein tor the reception of a drawing inatrument.

AARON WALDMAN. 

